Central belt lock, particularly for a parachute harness

ABSTRACT

A central belt lock, particularly for a parachute harness, includes a housing, a main pin or journal which is manually rotatable and axially movable therein, and an anchor plate which cooperates with a plurality of retaining bolts for the belt attachment or coupling members. There is dealt with the problem of allowing the belt attachment members to be released and thus disconnected from the lock even if the parachutist for some reason is unable to actuate the lock manually, after making a jump over the sea. Therefore, a central belt lock is provided to be activated by sea water and can be released thereby, without affecting the function thereof when operated manually. For this purpose, the main journal (2a) has at least one longitudinal bore in which a push rod (12) is mounted so as to be longitudinally movable. An actuator (20, 27) is associated with the push rod and is actuated when coming into contact with water, axially moving the push rod (12) and hence the anchor plate (5) with the retaining bolts (6). Preferably, the rotary handle (11a, 11b) of the belt lock contains an inner space (16) in which the actuator (20, 27) and the push rod as well as an angle lever serving as transfer members are accommodated.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a locking device for a central strap, i.e. acentral belt lock, particularly for a parachute harness, and comprises ahousing, a main pin or journal which is manually rotatable and axiallymovable therein, and an anchor plate which cooperates with a pluralityof retaining bolts for the belt attachment or coupling members. Centralbelt locks of this kind serve to release parachutists rapidly from theirparachutes after landing, so that they are not dragged over the groundor through water if the wind drives the parachute along.

2. Description of the Prior Art

Central belt locks having the features recited are already known, forexample from German Pat. Nos. 10 70 034, 12 05 321 and 20 43 634. Ineach case, the parachutist must actuate the belt lock himself by turningthe main journal manually by means of a preferably disc-shaped handle,and pressing it axially into the release position, with the result thatthe retaining belts are pulled out of the eyelets in the belt attachmentmembers, so that the body harness falls away from the person.

However, it may be that, as a result of shock, cold, or injury, theparachutist is not in a position to actuate his belt lock manually, anis consequently left in a largely helpless state in the harness. This isparticularly dangerous if the parachutist has fallen into the sea, sincehe can then be dragged down by the parachute and drown before rescuearrives. To avoid this danger, it has already been proposed that theconnecting member between the cords of the parachute and the shoulderstraps of the harness be released automatically, when they are submergedunder water, by using the higher conductivity of sea water effective viaelectrical or pyrotechnic means for such automatic release thereof. Thedisadvantage of this is that modifications of structure have to be madeto the harness and to the means for connection with the cords of theparachute.

SUMMARY OF THE INVENTION

Proceeding on the basis of the foregoing prior art as known anddescribed, an object of the present invention is to provide a centralbelt lock which contains an automatic release mechanism activated by seawater. The normal mechanical operation and manual actuation of the lockshould not be restricted or limited, and the size of the lock should notbe increased substantially. It is a further object that the mechanicalsecuring normally provided should be able to be bridged by the automaticrelease mechanism in the secured position of the lock, but otherwise thesame remains operational.

These objects are realized by a central belt lock which is characterizedprimarily in that the main journal has at least one longitudinal bore inwhich a push rod is mounted in such a way as to be longitudinallymovable, and an actuator being associated with the push rod, beingactivated upon contact with water, and axially displacing the push rodand hence the anchor plate with the retaining bolts.

The push rod may be secured against rotation relative to the mainjournal, and at its end facing the anchor plate it may have a narrowedportion and a bar, which pass through an opening in the anchor plate.

The push rod may cooperate with a locking member which secures itagainst axial displacement and releases it when the actuator isactivated.

The rotary handle of the belt lock may contain an inner space in whichthe actuator and transfer members or transmission means including asliding contact and an angle lever are accommodated. The actuator mayact on the push rod by means of the angle lever. Alternatively, theactuator may act on a liquid via a piston, and on the push rod via asecond piston.

The actuator may comprise a pyrotechnic element, at least one mechanicalspring, or a chamber filled with pressurized gas and a piston.

The actuation transfer or activating force output of the actuator mayact on a sliding contact which is movably mounted at right-angles to thepush rod and pushes against the angle lever by means of a projection orstep. The sliding contact may have a lug which engages in a groove inthe push rod, preventing the latter from moving axially.

The actuator may comprise two identical compression springs, mountedparallel to one another side by side, which act via a sliding contact onthe angle lever, which axially displaces the push rod. The helicalcompression springs may rest on an angle portion on the housing of therotary handle. The angle lever may be pivotably mounted on a bearingblock which rests on the housing of the rotary handle.

Laterally of the push rod, there may be mounted a pivotable lockinglever which in the locking position engages in a recess in the push rodand prevents the latter from moving longitudinally when the helicalcompression springs are clamped in place or tensioned. For pivoting thelocking lever out of the locking position and into the release position,an electromagnet activated by a sensor coming into contact with seawater, may be provided.

One advantage of the invention is the fact that conventional centralbelt locks can still basically be used, and no modifications to theharness are necessary. This means that parachutists do not have to adaptto new handles which differ from the customary handles; this alsocontributes to the degree of safety in the lifesaving operation. Theadaptation of locks already in use is readily possible with theinvention. The production of new locks according to the inventionrequires only comparatively little additional expense, since theessential components are unchanged.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show some embodiments of the invention which are describedhereinafter. In the drawings:

FIG. 1 is a diametric cross-sectional view taken through a conventionalcentral belt lock for a parachute harness;

FIG. 2 is a fragmentary diametric cross-sectional view taken through acentral belt lock having features according to the present inventionincludes a main journal having an axial bore and a push rod mountedtherein;

FIG. 3 shows the upper fragmentary diametric cross-sectional view takenthrough a lock according to the present invention having a rotary handlemounted above the housing and main journal, inside which areaccommodated the components for releasing the lock under the effect ofsea water;

FIG. 4 is a cross-sectional view similar to FIG. 3, but wherein adifferent actuator is provided for acting on the push rod; and

FIG. 5 is a plan or top view of the release mechanism shown in FIG. 4.

DETAILED DESCRIPTION

FIG. 1 shows the construction of a conventional central belt lock. Amain journal, stud or pin 2 is mounted in a rotatable and axiallymovable manner in a housing 1. In a tangentially and axially extendinggroove 3 on the periphery of the main journal 2, there slides aspring-loaded locking pin 4, which, in conjunction with locking stages(not shown) in the groove 3, ensures that the main journal 2 can executerotary and longitudinal movements only in certain directions, andengages in various positions provided for the functions of "applying orputting on", "secured" and "ejecting or taking off".

As a result of axial displacement of the main journal 2 in the downwarddirection in the "taking off" position, the lower end face of the mainjournal 2 presses against an anchor plate 5 on which a plurality ofretaining bolts 6 are formed, so that these bolts are connected to oneanother via the anchor plate 5. The retaining bolts 6 project upwardlyinto slots 7 in the housing 1, and are able to engage with and hold theeyelets (not shown in FIG. 1) of the belt attachment members of the bodyharness. As a result of displacement counter to the force of compressionsprings 14, the retaining bolts 6 release the harness.

Fixedly connected to the main journal 2 via a narrowed portion 8 thereis a bar 9 which passes through an oblong opening 10 in the anchor plate5 and prevents the anchor plate 5 from being accidentially moved. Onlyin the "putting on" position does the bar 9 take up a position relativeto the opening 10 such that the anchor plate 5, and hence also theretaining bolts 6, on being inserted into the eyelets of the beltattachment members, can move downwards.

The movements of the main journal 2 are effected manually by means of adisc-shaped rotary handle 11. The above-mentioned functions of the lockare engraved on the rotary handle.

FIG. 2 shows, according to the invention, a main journal 2a and a pushrod 12 which is mounted so as to be axially movable therein, and issecured against rotation by a planar surface 13 in a suitable recess inthe main journal 2a. At the lower end of the push rod 12 there areprovided a narrowed portion 8a and a bar 9a, the shapes of which aresimilar to the embodiment shown in FIG. 1, except that the narrowedportion and the bar are fixedly connected to the push rod 12, and not tothe main journal 2. As a result, the normal course of operation isunchanged, if the lock is released manually, as described with referenceto FIG. 1. However, independently of this, the push rod 12 may be pusheddownwards by means of suitable means in the main journal 2, and thus canmove the retaining bolts 6 out of the slots 7 without moving the mainjournal 2 in the rotary or longitudinal direction. In this way, the beltattachment members can be released automatically.

The entire lower part of a conventional central belt lock as shown inFIG. 1, namely the housing 1, anchor plate 5 with retaining bolts 6,compression springs 14 and cover 15, can be adapted or taken over forthe structure of the lock shown in FIG. 2. The main journal 2 may alsobe re-used, after being suitably reworked.

In the exemplary embodiments, in the rotary handle 11 of the belt lock,there is provided an inner space 16 enclosed by a handle housing 11a anda handle cover 11b. The base plate 17 of the rotary handle 11a, 11b isfixed to the main journal 2a by means of a hollow screw 18, and ispositively secured against rotation by means of a recessed planarsurface 19. The inner space 16 in the rotary handle may accommodatesuitable sensors, the actuator for actuating the push rod 12, andmechanical transfer members or transmission means from the actuator tothe push rod 12.

The actuator in the embodiment of FIG. 3 is a sensor means orpyrotechnic element 20 which acts on the end face 23 of the push rod 12via a sliding contact 21 and an angle lever 22; the sliding contact 21and the angle lever 22 are effective as the transfer members for theforce of the pyrotechnic element 20. When coming into contact withwater, the sensor means or pyrotechnic element 20 is ignited by asuitable electric circuit, so that its force of ejection moves the pushrod 12 downwards via the sliding contact 21 and the angle lever 22, andin this way opens the lock and releases the attachment members of theharness. This may happen within a fraction of a second.

Also mounted on the sliding contact 21 is a lug 24 which engages in agroove 25 in the push rod 12 and prevents the latter from movingaxially. When the pyrotechnic element 20 is ignited, the sliding contact21 first has to travel a distance "a" before the push rod 12 isreleased. For this purpose, a corresponding amount of play is providedon the angle lever 22. A compression spring 26 secures the slidingcontact 21 against accidental displacement.

FIGS. 4 and 5 show a further exemplary embodiment, namely a central beltlock with a mechanical actuator comprising two helical compressionsprings 27 which act on the push rod 12 via a sliding contact 21a andthe angle lever 22. At the other end, the helical springs 27 rest on thehousing 11a, 17 of the rotary handle 11 via an angle portion or flangemeans 28. The angle lever 22 is rotatably mounted on a bearing block 29(FIG. 5). A locking lever 30, which engages in a corresponding recess inthe push rod 12, locks the push rod 12 in the tensioned position of theactuator, which takes the form of the helical springs 27. If the lockinglever 30 is pivoted about its center of rotation 31, for example bymeans of an electromagnet (not shown), it releases the push rod 12, sothat the latter is pushed downwards by the compression springs 27 bymeans of the angle lever 22.

A further embodiment, not shown in the drawings, provides that theactuator is a chamber filled with pressurized gas, the pressure of whichis transmitted to the push rod 12 via a piston. Finally, the force ofany desired actuator may be transmitted to a liquid via a piston, andmay then be deflected onto the push rod 12 by means of an additionalpiston.

The central belt locks constructed according to the present inventionmay make a substantial contribution to ensuring that parachutistsequipped with them have a comparatively greatly increased chance ofsurvival if they have to jump over the sea. This is particularlyimportant for military use, and in organizations for rescuing shipwreckvictims, since the missions flown are usually or always over the sea.The results or advantageous effects of the invention described above areattained with comparatively limited equipment, and at correspondinglylow cost. Moreover, existing belt locks of conventional construction canbe modified.

The features of the object of the application disclosed in thedescription, drawings, and claims may be essential to the variousembodiments of the invention both individually and in any desiredcombination with one another.

We claim:
 1. A central belt lock, especially forparachutists-body-belts, comprising:a housing having an inside surface;a main journal which is manually rotatable and axially movable in saidhousing, said main journal being provided with at least one longitudinalbore; an anchor plate operatively connected with said housing andarranged with a plurality of retaining bolts for belt attachmentmembers; a push rod operatively connected with said anchor plate andmounted in each longitudinal bore of said main journal, so that saidpush rod is longitudinally movable; an actuator operatively connectedwith said push rod, said actuator including a sensor means operativelytriggered upon contact with water for axial displacement of said pushrod and hence of said anchor plate with said retaining bolts; a rotaryhandle provided with said main journal for effecting manual rotation andaxial movement, said rotary handle including an inner space whichaccommodates said actuator and transfer members for transferringmovement from said actuator to said push rod; said transfer membersincluding an angle lever having operative pivotal mounting relative tosaid housing and via which said actuator acts on said push rod; and asliding contact which is mounted and arranged to be movable at rightangles to said push rod; said sliding contact with said angle levercomprising said transfer members, said sliding contact being providedwith a projection, with the movement of said actuator acting on saidsliding contact for sliding movement of the sliding contact upon theinside surface of the housing so as to provide operative connectioneffective in pushing said projection thereof against said angle lever.2. A central belt lock according to claim 1, in which said push rod isprovided with a groove, and said sliding contact is provided with a lugfor engaging said groove and preventing axial movement of said push rod.3. A central belt lock according to claim 1, in which said rotary handleincludes a handle housing; and which includes a bearing block arrangedon said handle housing and securely connected therewith, said anglelever being pivotably mounted on said bearing block.
 4. A central beltlock according to claim 1, in which said anchor plate is provided withan opening; said push rod including anti-rotation means so that saidpush rod is kept from any rotation relative to said main journal; saidpush rod having a first end remote from said anchor plate, and a secondend facing said anchor plate and extending through said opening; andsaid second end of said push rod being provided with a narrowed portionand a bar which via said opening in said anchor plate cooperate toprevent said anchor plate from being accidentally moved.
 5. A centralbelt lock according to claim 4, which includes a locking memberconnected with said housing and with said push rod for securing saidpush rod against axial displacement and for releasing said push rod whensaid actuator is activated.
 6. A central belt lock according to claim 1,in which said actuator includes a pyrotechnic element.
 7. A central beltlock according to claim 1, in which said actuator includes two helicalcompression springs having parallel relationship to one another; andincluding ends thereof that act on said angle lever for axiallydisplacing said push rod.
 8. A central belt lock according to claim 7,in which said rotary handle includes a handle housing which is providedwith a flange means; and in which said compression springs engage saidflange means.
 9. A central belt lock according to claim 7, in which saidpush rod is provided with a recess, and which includes a locking leverpivotably mounted in said housing and located laterally of said pushrod, said locking lever, in the locking position, engaging said recessof said push rod to prevent the latter from moving longitudinally whensaid one of said compression springs is tensioned.
 10. A central beltlock according to claim 9, said actuator includes an electromagnetplaced therewith and actuated by a water-sensitive sensor for pivotingsaid locking lever out of the locking position and into a releaseposition.